Propeller



y 956 H. H. HOKE, JR 2,755,867

PROPELLER Filed Aug. 13, 1951 2 Sheets-Sheet 2 ATTORNEY PROPELLER Harry H. Hoke, Jr., Washington, D. C. Application August 13, 1951, Serial No. 241,513

4 Claims. (Cl. 170-156) The object of the invention is to provide a propeller for watercraft that will not be subject to the disadvantages inherent in conventional screw propellers, such as the creation of a partial vacuum ahead of the propeller tending to exert a back pressure on the vessel; to provide a propeller adapted for pulling as well as for pushing, so that it may be installed and used at the forward end as well as the stern end of the equipped craft; to provide a propeller composed of a plurality of assembled parts, so that in the event of damage, the afiected part may be replaced; and to provide a propeller which is a simple form, susceptible of cheap manufacture and highly eflicient in operation.

With this object in view the invention consists in a construction and combination of parts of which a preferred embodiment is illustrated in the accompanying drawings wherein:

Figure 1 is a side elevational view of a submarine modified to incorporate the invention;

Figure 2 is a sectional diametrical view of the improved propeller.

Figure 3 is a side elevational view of the same;

Figures 4 and 5 are transverse sectional views on the lines 44 and 5-5 respectively of Figure 2;

Figure 6 is a diagrammatic view showing the layout of the propeller blade;

Figure 7 is a sectional view at the forward end of the craft shown in Figure 1, illustrating the mounting of the propeller on crafts of this type; and

Figure 8 is an elevational view of the spider.

To obviate the back pressure inherent in the use of conventional screw propellers, in whose operation a partial vacuum is created just ahead of them, it is proposed to use both at the forward end and stern end of a vessel, such as the submarine shown at 10 in Figure 1, a propeller which will be free of these disadvantages. In the present instance, this propeller consists of a conical body 11, its shape being that of a cone of revolution, or right circular cone. This body is encircled by blades 12, extending from the nose of the body or apex of the cone and terminating at the base of the latter.

Since in encircling the body the blades will perforce increase in diameter and since the body will have a constant angular speed in operation, in order to distribute the pull uniformly on the blade, the spiral angle of the same is progressively increased, as clearly appears in Figure 6 of the drawings, wherein, at the nose end, the pitch is shown to be the longest and at the base end the shortest, the intermediate portion having a length intermediate between the two. But it is proposed to have a plurality of such blades 12 and their angular spacing is uniform. In the present instances four are shown and accordingly they are angularly spaced 90.

The body is made in sections each of which is a 90 segment. This because the number of blades employed is four. Were the number of blades increased to five, the segments would be 72, and so on. This so that the tates Patent 2,755,867 Patented July 24, 1956 exterior surface of each segment will hold portions of a blade corresponding to equivalent portions of another blade on another segment. Thus the propeller and blades may be built up by assembling the segments, or in case of damage, substituting for the damaged segment, its equivalent in a new segment.

The blades are formed on the assembled segments, 11a, 11b, 11c, and 11d, and these segments are laid on the spider 14 to which they are connected by rivets 15 passing through the segments and through ribs 14a which are spaced by the rings 14b. At the nose 13, the segments are screwed by cap screws 15a. The hub 17 of the spider is co-axial with the bore in the nose 13 and through this hub and into the nose is inserted the tubular drive shaft 18, the latter being keyed in the nose and keyed in the hub, to prevent any relative turning movement of the propeller and its shaft.

The shaft is journalled in the nose 19 of the vessel, as indicated at 20. And interior to the vessel is coupled to its prime mover, shown at 21 in Figure 7 of the drawing but not elsewhere.

If the propeller abuts the nose, as indicated in Figure 2, that is, if it substantially abuts the end, the bearing 22 is provided forward of the bearing 20, this being coupled to the vessel and preferably carrying a suitable packing between it and the bearing 20.

In the construction shown in Figure 7 the nose of the vessel is progressively reduced in diameter, so that the heel end of the propeller or body may surround it, as shown at 23 in Figure 7.

It is obvious that in the use of the propeller, it will not only thread its way effectively through the water but will tend to throw the latter to the side and thus carry the vessel forward, the shape being such that the water is parted at the forward end of the vessel and any tendency to vacuum creation at the rear end is obviated by the tendency to force the water in against the rear face of the propeller.

The invention having been described, what is claimed as new and useful is:

1. A propeller comprising a cross-sectionally circular body of progressively increasing diameter, and a blade encircling the body and defining a spiral path therearound, the blade being of constant width throughout and having its spiral angle constantly increasing at a rate to provide a progressively reduced pitch from a point at the least diameter of the body to a point at the greatest diameter thereof.

2. A propeller comprising a body in the form of a cone of revolution and a blade encircling the body and defining a spiral path therearound, the blade being of uniform width throughout its length and having its spiral angle progressively increasing at a rate to provide a progressively reduced pitch from the apex of the body to the base thereof.

3. A propeller comprising a body composed of identical segments assembled to define a right circular cone, and a plurality of blades encircling the body and defining a spiral path therearound, the blades and the segments being equal in number and the former being of uniform width throughout, uniformly spaced angularly and having identical spiral angles progressively increasing at a rate to provide a progressively reduced pitch from the apex of the body to the base thereof.

4. A propeller comprising a conical spider having an axial bore, a shaft entering said bore and keyed therein, and a plurality of identical conical segments removably secured to said spider, the segments being exteriorly formed with propeller blades equal in number to the number of segments, the blades being uniformly spaced angularly, being of uniform width throughout and encircling the segments in spiral paths with the spiral angle References Cited in the file of this patent UNITED STATES PATENTS 2,294. Fitzgerald Oct. 11, 1841 4 Webster et a1. Apr. 13, 1883 De Los Rios July 2, 1912 Taber June 12, 1923 Mertens June 6, 1939 FOREIGN PATENTS Great Britain July 24, 1924 France Nov. 7, 1941 

